What is the difference between AppBarLayout vs Toolbar?

The AppBarLayout is used to achieve various scrolling behaviors such as collapse, flex space, and quick return.

http://www.google.com/design/spec/patterns/scrolling-techniques.html

http://android-developers.blogspot.com/2015/05/android-design-support-library.html

If you want just to include the Toolbar without any scrolling effects you can use Toolbar. But if you want to make some scrolling effects like on the images you need to use AppBarLayout.

More here and here.